We already have a karma system, though any karma system is completely useless in my mind. Constructive posts should be able to stand on themselves without leaning on the reputation of the poster.
Discriminating between paying users and free users is disgusting. The modding community is already discutable as-is, with paid exclusive mods and paid GTA:O cheating, there's absolutely no reason to make this place as toxic as the rest by throwing in money-for-reputation.
@FelixTheBlackCat you can look up GTAV C# tutorials on YouTube for a visual explanation. Since you already have the .cs, you can create a new C# project (any template I guess, I'd go with Class Library), replace the code in the generated .cs with your own (or delete it and add your .cs through the Project tab -> Add Existing Item).
Then right-click References -> Add References -> Browse -> Select the scripthookvdotnet.dll file and click Okay.
Optionally, you can go to Project -> Properties -> Build Events -> Post-Build event command line and enter a directory that you would like to send a copy of the dll to, like so:
COPY "$(TargetDir)$(TargetFileName)" "C:\Program Files\Rockstar Games\Grand Theft Auto V\scripts"
Finally, you can go to the Build tab and click Build Solution or Build [Project name] to build the dll and have a copy of it sent to the directory you indicated above.